[Mapserver-users] Edges of Images

Fri Oct 17 15:52:11 PDT 2003

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Benjamin -
=20
Set the map image background to white and then use the OFFSITE 255 255 =
255 statement in the data layer to make all white pixels transparent =
(assuming the no-data value really is exactly that value).  This will =
cause areas of white that overlap another tile to disappear, and any =
valid data pixels that are white will expose the white background and =
show up as white.
=20
    - Ed
Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242=20

-----Original Message-----
From: Benjamin Wragg [mailto:bwragg at tpg.com.au]
Sent: Friday, October 17, 2003 6:43 PM
To: mapserver-users at lists.gis.umn.edu
Subject: [Mapserver-users] Edges of Images

Hi,
=20
I'm currently using 8 satalite image tiles of the world (referenced in =
lat/longs) in Mapserver as shown below:
=20

--------------------------
A1 | A2 | A3 | A4 |
--------------------------
B1 | B2 | B3 | B4 |
--------------------------
=20
If I zoom into the lower right tile (B4) I can see a large white band =
running top to bottom where the tile finishes just right of New Zealand. =
Someone has asked me if it's possible for Mapserver to automatically =
display the next logical tile (which would be B1) to stop the ugly white =
band. Any ideas?
=20
Cheers,
=20
Benjamin Wragg
=20

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<DIV><SPAN class=3D529495022-17102003><FONT face=3DArial color=3D#0000ff =

size=3D2>Benjamin -</FONT></SPAN></DIV>
<DIV><SPAN class=3D529495022-17102003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D529495022-17102003><FONT face=3DArial color=3D#0000ff =
size=3D2>Set=20
the map image background to white and then use the OFFSITE 255 255 255 =
statement=20
in the data layer to make all white pixels transparent (assuming the =
no-data=20
value really is exactly that value).  This will cause areas of =
white that=20
overlap another tile to disappear, and any valid data pixels that are =
white will=20
expose the white background and show up as white.</FONT></SPAN></DIV>
<DIV><SPAN class=3D529495022-17102003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D529495022-17102003>    <FONT =
face=3DArial=20
color=3D#0000ff size=3D2>- Ed</FONT></SPAN></DIV>
<DIV><SPAN class=3D529495022-17102003>
<P><FONT size=3D2>Ed McNierney<BR>President and Chief =
Mapmaker<BR>TopoZone.com /=20
Maps a la carte, Inc.<BR>73 Princeton Street, Suite 305<BR>North =
Chelmsford,=20
MA  01863<BR>ed at topozone.com<BR>(978) 251-4242 =
</FONT></P></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B> Benjamin Wragg=20
  [mailto:bwragg at tpg.com.au]<BR><B>Sent:</B> Friday, October 17, 2003 =
6:43=20
  PM<BR><B>To:</B> mapserver-users at lists.gis.umn.edu<BR><B>Subject:</B>=20
  [Mapserver-users] Edges of Images<BR><BR></FONT></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2>Hi,</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial size=3D2>I'm =
currently=20
  using 8 satalite image tiles of the world (referenced in <SPAN=20
  class=3D484472822-17102003><FONT face=3DArial size=3D2>lat/longs) =
</FONT></SPAN>in=20
  Mapserver as shown below:</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV>
  <DIV><SPAN class=3D484472822-17102003>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2>--------------------------</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial size=3D2>A1 | =
A2 | A3 | A4=20
  |</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2>--------------------------</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial size=3D2>B1 | =
B2 |=20
  B3 | B4 |</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2>--------------------------</FONT></SPAN></DIV></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial size=3D2>If I =
zoom into the=20
  lower right tile (B4) I can see a large white band running top to =
bottom where=20
  the tile finishes just right of New Zealand. Someone has asked me if =
it's=20
  possible for Mapserver to automatically display the next logical tile =
(which=20
  would be B1) to stop the ugly white band. Any =
ideas?</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2>Cheers,</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial =
size=3D2>Benjamin=20
  Wragg</FONT></SPAN></DIV>
  <DIV><SPAN class=3D484472822-17102003><FONT face=3DArial=20
  size=3D2></FONT></SPAN> </DIV></BLOCKQUOTE></BODY></HTML>

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